Drivehead grounding rod



April 1951 G. c. SALMONS 2,547,176

DRIVEHEAD GROUNDING ROD Filed Oct. 23, 1948 g eaye C da hwm PatentedApr. 3, 1951 UNITED STATES PATENT OFFICE A. B. Chance Company,Centralia, Mo., a

poration of Missouri Application October 23, 1948, Serial N 0. 56,123

4 Claims.

The present invention relates to drive head grounding rods, and isparticularly concerned with the provision of an improved grounding rodhaving adequate contact with the earth, and also having a strong andpermanent electrical connection with a maximum contact area between thegrounding rod and the ground wire.

One of the objects of the invention is the provision of a grounding rodwhich is simple and cheap to construct, but which is adapted to beprovided with a minimum contact resistance connection to ground wires ofdifferent sizes.

Another object of the invention is the provision of an improvedgrounding rod which has good contact with the earth into which it isdriven, but which can be readily salvaged by pulling the rod out whenits period of service is over.

Another object of the invention is the provision of an improvedgrounding rod assembly which is economical to manufacture, sturdy,efficient, and adapted to be driven easily without damage to the rod.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which similarcharacters of reference indicate similar parts throughout the severalviews.

Referring to the single sheet of drawings accompanying thespecification,

Fig. 1 is a fragmentary side elevational view of a ground rod assemblydriven into the earth;

Fig. 2 is a fragmentary side elevational view of the ground rod head andconnector, on a larger scale and in partial section;

Fig. 3 is a fragmentary side elevational view of a ground rod head, seenfrom the right of Fig. 2, with the wedging contact removed;

Fig. 4 is an axial sectional view, taken on the plane of the line 4-4 ofFigure 2, looking in the direction of the arrows;

Fig. 5 is a fragmentary end elevational view of a modification;

Fig. 6 is a fragmentary side elevational view in partial section; and

Fig. '7 is a view in perspective of the tapered contact-wedging memberused in Figures 5 and 6.

Referring to Fig. 1, it) indicates in its entirety the ground rodassembly, which includes a ground rod l I, having a relatively narrowcylindrical shank 12 provided with a round or conical point l3.

It will be noted that the absence of a head behind the point, such as isfrequently employed with anchor rods, makes the present rod have abetter contact with the surrounding earth. With a guy rod sometimes usedfor grounding, the head makes a hole larger than the shank so that thereis defective contact between the shank and the earth due to the enlargedhole formed by the head.

At its upper end the ground rod H has an enlargement l4 and may have afrusto-conical tapered portion [5 between the cylindrical shank l2 andthe enlargement l4. Above the frusto conical enlargement there may beanother frusto-conical portion [6, which terminates at the angular ridgeH, but is integrally joined to a tapering frusto-conical portion IS, thelatter terminating in a fiat head 19, which may also be convex.

The body 14 of the head is provided with a through bore 20, having agradual taper and being frusto-conical in shape. The enlargement I4 isgenerally cylindrical on the sides 34 and 35, which are engaged by thewasher 3| and by the wedging member 23 in bore es. On the sides 36 and31 (Fig. 3) the enlargement i l may taper downwardly, to save material;but the side 34 in particular should be straight up and down to give agood bearing surface against the washer 3|.

The ground rod shank I2 is preferably provided with its drive head byhaving the head forged on the end of the rod.

The through bore 20 is formed with a pair of or diameter.

face and these grooves are adapted to receive ground wires 23 ofdifferent sizes. Smaller ground wires are placed in the groove 22, andthe larger ones in the groove 25; but it is only necessary that thediameter of the Wire be large enough so that the wire will protrude fromthe groove.

An enlongated and gradually tapered frustoconical wedging member 23 iprovided, having the fiat end surface 24. The taper of the wedgingmember 23' corresponds to that of the through bore 20; and the wedgingmember '23 has a cylindrical through bore 25. A screw bolt 25 has itshead 21 engaging the flat end 24 of the wedging member 23, and has itsshank 28 passing through the bore 25 and provided with a threadedportion 29 for receiving a nut 30.

A washer 3| is preferably provided on the threaded end of bolt 26, aswell as a spring lock washer 32; and the end of the bolt is 'mushroomedover at 33 to prevent the loss of the bolt nut and other parts from thegrounding rod.

When a wire, such as the wire 23, is inserted in the appropriate groove2|, as shown in Fig. 4, and engaged by the wedging member 23, tighteningof the nut 30 on the bolt 25 will cause the wedging member 23 to bedrawn very tightly into engagement with the wire 23. The wire may beslightly flattened and caused to conform to the shape of the groove andthe shape of the wedging member 23; but a very efficient connection,with low contact resistance, is thus provided.

The nut 39 may be driven home until the spring lock washer 32 is rigidlyengaged by the nut; but if the metal of the ground wire should flowwhile cold, the wedge 23 will not loosen, since the expansion of thespring washer 32 still tends to keep the assembly tight.

The operation of the ground rod will be ap-- parent from the descriptionof its parts. It is driven into the ground, as shown in Fig. l; and theground wire attached as shown in Figs. 1 and 2. Such a ground hasfrequent application in the case of transmission lines, and provides amuch better ground than if reliance is placed upon guy cables and guyrods.

Referring to Figures 5, 6 and 7, these are views showing modificationsin which the grooves are made in the wedging member instead of thetapered bore in which it is received.

Referring to Figures 5 and 6, the ground red head 35 in this embodimentis preferably provided with the front and rear plane surfaces 36,

31, and the tapered bore 38 runs from one surface 35 to the other 3i.The head 35 is provided with vthe same cylindrical shank II, and theshape of the head 35 in front elevation is substantially circular, asseen in Figure 5.

The head 35 tapers and has a curved side surface at 39 extendingdownward toward the shanls i i. At its upper end the head 35 preferablyhas a cylindrical extension iii, with a flat upper surface ii forengagement with the sledge. The wedging member 42 in this case has athrough bore 63 and plane surfaces at and 45 at its ends.

Between the ends it, 45 the wedging member 42 has a frusto-conicalsurface it which is complementary to the tapered frusto-conical bore ilin head 35. In this modification the wedging member 52 is provided withtwo or more half cylindrical grooves 3, 59, located. longitudinally ofits frusto-conical surface for receiving the ground wire. The operationof this modification is substantially the same as that of Figures 1While I have illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention, and I do not wish to be limited to the precise details ofconstruction set forth, but desire to avail myself of all changes withinthe scope of the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters'Patent of the United States, is:

1. In a drive head grounding rod, an integral member having a thincylindrical shank with a sharp point, a round enlargement at the upperend of said shank, said enlargement being provided with a taperedthrough bore, and a wedging member of complementary shape located insaid bore and having a through bore insaid wedging member, a screw boltin said \vedging member having a nut engaging the side of said head, thehead of said screw bolt enaging the larger end of said wedging member,there being a partially cylindrical groove located between said wedgingmember and the through bore in said enlargement for receiving andclamping a ground wire, the said groove being located in the wedgingmember and extending longitudinally of its tapered surface.

2. In a drive head grounding rod for maintaining constant low resistancecontact with a grounding wire, comprising a thin elongated metal memberprovided with a point for driving deeply into the ground with a minimumamount of resistance to the drive head, said member having an enlargedhead provided with a flat driving surface on its upper end, saidenlarged head being provided with opposed fiat surfaces on its oppositesides and having a frusto-conical tapered bore extending from one fiatside to the other flat side, a substantially complementary frustoconicalmetal member fitting in said tapered bore, and having a cylindricalthrough bore and a plane surface on its larger end, said frustoconicalmetal member being provided in its tapered surface with a longitudinallyextending substantially half cylindrical groove for receiving the groundwire, a screw bolt extending through said through bore, and providedwith a metal thrust plate engaging the flat side of the enlargement atthe smaller end of the tapered bore, said bolt having its head engagingthe plane surface at the larger end of the frusto-conical member andbeing provided with a spring washer outside of said thrust plate, andwith a nut engaging said spring washer, the frusto-con'ical metal memberbeing drawn into the tapered bore with a ground wire in said grooveuntil the frustoconical metal member engages the walls of the taperedbore, and the ground wire is deformed in said groove to establish atight low resistance contact between the ground wire and the groundingrod, the nut driving the spring washer on the bolt to a rigid conditionbut the spring washer being of suflicient strength to take up anylooseness between the ground wire and the groove and the walls of saidtapered bore which may be caused by the flow of the metal to establish alow resistance connection.

3. In a drive head grounding rod for maintaining constant low resistancecontact with a grounding wire, comprising. a thin elongated metal memberprovided with a point for driving deeply into the ground with a minimum.amount of resistance to the drive head, said member. having an enlargedhead provided with aflat driving surface on its upper end,- saidenlarged head being provided with opposed fiat surfaces on its oppositesides and having a frusto-conical tapered bore extending from one flatside to the other flat side, a substantially complementaryfrusto-conic'al metal member fitting in: said tapered bore, and having acylindrical through bore and a plane surface on. its larger end, saidfrusto-conical metal member bein provided in its tapered surface with alongitudinally ex tending substantially half cylindrical. groove forreceiving the ground wire, a screw bolt extending through said throughbore,.and provide'dawith a metal thrust plate". engaging the flat side;of the enlargement at the smallere'ndi of the tapered bore, said bolthaving its head engaging. the plane surface at the larger end of thefrusto conical member andrbein'g provided witlica spring washer outsideof said thrust plate,- and with a nut engaging said spring washer, thefrustoconical metal member being drawn into the tapered bore with aground wire in said groove until the frusto-conical metal member engagesthe walls of the tapered bore, and the ground Wire is deformed in saidgroove to establish a tight low resistance contact between the groundwire and the grounding rod, the nut driving the spring washer on thebolt to a rigid condition but the spring washer being of sufficientstrength to take up any looseness between the ground wire and the grooveand the walls of said tapered bore which may be caused by the flow ofthe metal to establish a low resistance connection, the saidfrusto-conical member having a plurality of said cylindrical grooves ofdifferent sizes to be used with different sizes of ground wires.

4. In a drive head grounding rod for maintaining constant low resistancecontact with a grounding wire, comprising a thin elongated metal memberprovided with a point for driving deeply into the ground with a minimumamount of resistance to the drive head, said member having an enlargedhead provided with a flat driving surface on its upper end, saidenlarged head being provided with opposed fiat surfaces on its oppositesides and having a frusto-conical tapered bore extending from one flatside to the other flat side, a substantially complementaryfrusto-conical metal member fitting in said tapered bore, and

having a cylindrical through bore and a plane surface on its larger end,said frusto-conical metal member being provided in its tapered surfacewith a longitudinally extending substantially half cylindrical groovefor receiving the ground wire, a screw bolt extending through saidthrough bore, and provided with a metal thrust plate engaging the flatside of the enlargement at the smaller end of the tapered bore, saidbolt having its head engaging the plane surface at the larger end of thefrusto-conical member and being provided with a spring washer outside ofsaid thrust plate, and with a nut engaging said spring washer, thefrusto-conical metal member being drawn into the tapered bore with aground wire in said groove until the frusto-conical metal member engagesthe walls of the tapered bore, and the ground wire is deformed in saidgroove to establish a tight low resistance contact between the groundwire and the grounding rod, the nut driving the spring washer on thebolt to a rigid condition but the spring washer being of sufficientstrength to take up any looseness between the ground wire and the grooveand the walls of said tapered bore which may be caused by the flow ofthe metal to establish a low resistance connection, the said bolt havingits threaded end deformed to prevent the removal of the nut and tomaintain a permanent assembly of the parts even while loose.

GEORGE C. SALMONS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 698,180 Deviese Apr. 22, 19021,001,054 Lawrence Aug. 22, 1911 1,241,497 Coleman Oct. 2, 19172,007,357 Anderson July 9, 1935 FOREIGN PATENTS Number Country Date316,336 Germany May 17, 1918

